In the operation of an elevator system, an essential piece of information is the call data entered by users to define their destination floor. A passenger using the elevator system has to inform the control system of the elevator system regarding both his/her own arrival floor and his/her destination floor that the user is heading for. Traditionally, these call data items are entered by the passenger in two steps by first entering a hall call on his/her arrival floor typically by pressing arrow buttons and then, upon arrival of an elevator at the passenger's starting floor, entering his/her destination floor data to the system by pressing a car call button placed in a control panel inside the elevator car. Due to its two-step nature, the traditional system requires that the elevator passenger enter two separate calls for one elevator ride, unless an elevator happens to be present at the passenger's arrival floor or unless another person traveling in the same direction has entered a hall call.
The number of calls to be entered for one elevator ride can be reduced to one by using a so-called destination control system. In the destination control system, the passenger feeds his/her destination floor call into a destination call device while still outside the elevator on a floor level. Thus, the user only has to enter a call once as the up and down calls are omitted. Based on this one call, the elevator system allocates the most suitable elevator to the customer, and when the customer boards the elevator car no separate destination call needs to be entered in the car.
Destination control requires the use of a special destination call device that allows the input of all possible floor numbers and floor identifiers to the elevator control system. Often the destination call device contains numeric keys 0-9 for the input of calls. A destination call can also be entered to the elevator system via a wireless and portable transmitter. The call can be registered in the elevator control system in the same way as if the call had been entered via a traditional control panel in the car. The destination floor can be selected by keying in the desired floor into the portable transmitter. A receiver for receiving the destination call as well as the associated antenna may be placed in the lobby or in the control panel of the elevator car. It is thus possible to input a destination call by wireless means from the lobby from outside the car.
The destination call regarding the destination floor entered by the user as well as the starting floor data obtained from the destination call device are transmitted to the elevator control system for elevator allocation. The person having entered the destination call is guided by means of the call device to the elevator allocated to him/her.
A problem with prior art solutions is that the user does not necessarily board the elevator allocated to him/her. The elevator control system never gets information indicating that the person having entered a call does not board the elevator intended for him/her e.g. in a case where the elevator allocated to the person is full. Neither is the elevator control system informed that the person having originally entered the destination call is still waiting for an elevator and that a new elevator should be allocated to him/her.